1. Field of the Invention
The present invention relates to alarms, and more particularly pertains to a new and improved audible alarm activated by a mercury switch specifically adapted for use with display cases. Many individual collectors of various assorted valuable items such as coins, gem stones, jewelry, guns, etc. frequently travel to display these items at shows. These various valuable collectible items are transported and displayed in display cases and frames. At a collector's show, these display cases and frames are placed horizontally on tables disposed in a large room. Because these shows are typically open to the general public, there is a high volume of traffic by a wide Variety of individuals past these various display cases. While the conventional display cases may be provided with various types of mechanical locks, this does not prevent individuals from stealing the entire display case. In order to deter this theft, the present invention provides an audible alarm which may be mounted in the interior of the display cases which is actuated by a sensitive mercury switch.
2. Description of the Prior Art
Various types of alarms are known in the prior art. A typical example of such an alarm is to be found in U.S. Pat. No. 2,041,577, which issued to C. Sutherland on May 19, 1936. This patent discloses a tear gas dispenser actuated by a mercury switch which is concealed within an artificial packet of money. the mercury switch is in the form of a V-shaped tube with conductors located at the end portions of the V-shaped tube. U.S. Pat. No. 3,710,371, which issued to G. Whalen et al on Jan. 9, 1973, discloses a portable alarm system which includes a mercury switch connected to trigger a latching type semiconductor switch, causing electrical current to energize an alarm. Once sounded, the alarm cannot be silenced unless the correct procedure or key method is followed. U.S. Pat. No. 4,284,984, which issued to J. Scarpino et al on Aug. 18, 1981, discloses an attitude change alarm for securing articles from theft or other undesired movement. The alarm includes a case having a wall which defines a hollow interior. Resistive elements are maintained within the wall in spaced relationship with each other and in common communication with an electrically conductive surface on the outside of the wall. When the alarm is moved, a current is transmitted from a conductor through the resistive elements and is passed through a transformer which activates the alarm. Various geometrical configurations of the attitude change alarm include spherical, oval, hexagonal and conical shaped recesses which enclose pools of mercury. U.S. Pat. No. 4,462,023, which issued to C. Nielsen et al on July 24, 1984, discloses a position sensitive alarm which is adapted to be mounted to an item of personal property to be protected so that if the property is moved, an audible alarm is produced. The alarm includes a housing in which a battery, a buzzer and a position sensitive switch are mounted therein. An aperture is cut in the housing so that the sound produced by the buzzer does not muffle within the housing. The components within the housing are fully enclosed except for the battery. The batteries are mounted within the open side of the battery case, which itself is mounted within the housing. The circuit, lacking an on/off switch is disarmed and armed by removal and replacement of the battery in the battery case.
While the above mentioned devices are suited for their intended usage, none of these devices disclose an audible alarm activated by a mercury switch mounted in a generally L-shaped housing for location in an interior corner portion of a display case. Additionally, none of the aforesaid alarm devices utilize a mercury switch having a conical recess containing a pool of mercury and having a conductor ring extending around a top portion of the recess and encapsulated in a block of plastic material. Furthermore, none of the aforesaid alarm devices utilize a mercury switch having a conical recess containing a pool of mercury and spaced concentric conductor rings encapsulated in a block of plastic material. Inasmuch as the art is relatively crowded with respect to these various types of alarms, it can be appreciated that there is a continuing need for and interest in improvements to such alarms, and in this respect, the present invention addresses this need and interest.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of alarms now present in the prior art, the present invention provides an improved display case alarm. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved display case alarm which has all the advantages of the prior art alarms and none of the disadvantages.
To attain this, representative embodiments of the concepts of the present invention are illustrated in the drawings and make use of an L-shaped housing which encloses a battery, an audible alarm, a mercury alarm activation switch and an alarm enable/disable switch. When the alarm is mounted in an interior corner portion of a display case, the ends of the legs of the L-shaped housing abut adjacent interior side walls of the display case, forming a protected rectangular space for the alarm enable/disable switch. The alarm is turned on and off by a key inserted through a small hole drilled through one side wall of the display case. The key for the alarm enable/disable switch may be in the form of a cylindrical pin for a simple push button type switch, or may have specially formed projections for engagement with a cooperating recess formed in the enable/disable switch for a rotary type switch. The audible alarm is set off by a mercury type switch. Two separate embodiments of a highly sensitive mercury type switch are disclosed. In a first embodiment, an interior conical recess in a block of a plastic material contains an encapsulated pool of mercury. A conductor ring extends around a top portion of the recess and a second conductor is inserted into the mercury pool through the apex of the conical recess. In a second embodiment two spaced ring shaped conductors extend coaxially adjacent a top portion of a conical recess which contains a pool of mercury. The conductor rings and the mercury pool are encapsulated in a block of plastic.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new and improved display case alarm which has all the advantages of the prior art alarms and none of the disadvantages.
It is another object of the present invention to provide a new and improved display case alarm which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new and improved display case alarm which is of a durable and reliable construction.
An even further object of the present invention is to provide a new and improved display case alarm which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such alarms economically available to the buying public.
Still yet another object of the present invention is to provide a new and improved display case alarm which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new and improved display case alarm which utilizes a generally L-shaped housing for mounting in a protected interior corner of a display case.
Yet another object of the present invention is to provide a new and improved display case alarm which is activated by an improved form of mercury switch.
Even still another object of the present invention is to provide a new and improved display case alarm which utilizes a mercury switch having a pool of mercury in a conical recess encapsulated in a block of plastic material.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.